Thin-film microbattery charged by latent heat?

Micro-batteries are small batteries typically integrated with the microsystem for which they provide the power. This microsystem can be a wireless sensor for the internet of things, a smart pill for medical diagnosis and smart drug delivery or an embedded chip in for example a smart card. The main issue with micro-batteries is the small energy they can carry, which is intrinsically the case for the small footprint and available volume for charge storage. Therefore, these tiny energy storage devices are typically combined with an on-board energy-harvester such as an infrared photo-voltaic cell to be able to recharge the battery when idle. Of course, this harvester also takes up space and for true autonomous microsystems (i.e. no external connections possible), management of available space is critical. In this project, we look at the possibility of combining storage and harvesting in a single device for space and thus energy optimization in a microsystem. These new type of combined harvester and energy storage devices have been nick named "harvestorers". Specifically, we are integrating thin-film batteries on silicon substrates. At imec, we have developed 3D structuring of the substrate to increase the footprint capacity of the micro-battery. In a next step, we want to evaluate the possibility of using latent heat the charge the battery. Galvano-thermal cells have been known for a long time. A temperature difference between two same half-cells creates a voltage difference simply as a result of thermodynamics (Nernst equation for electrode equilibrium potential). The problem with these "large" cells is that the potential difference (energy) is very small and thus not useful for applications. However, at the micro-and nano-scale we can take advantage of nanoionics to optimize ionic transport. The work will involve deposition of and testing of suitable thin-film stacks. The design for the placement and spacing of anodes and cathodes will be critical for optimal harvesting. The state-of-the-art nanofabrication facilities of imec and a fully equipped battery lab are at the disposal for the researcher.

Required background: Engineering Technology and Science

Type of work: 80% experimental, 20% design

Supervisor: Philippe Vereecken

Daily advisor: Nouha Labyedh, Maarten Mees

The reference code for this position is 1812-76. Mention this reference code on your application form.